JournalArticle1346701Discovering shared conceptualizations in folksonomies2008J\"{a}schkeRobertHothoAndreasSchmitzChristophGanterBernhardStummeGerd38-536 ISSN: 1570-8268 DOI: http://dx.doi.org/10.1016/j.websem.2007.11.004Elsevier Science Publishers B. V.Amsterdam, The Netherlands, The NetherlandsWeb Semant.1http://portal.acm.org/citation.cfm?id=1346701Social bookmarking tools are rapidly emerging on the Web. In such systems users are setting up lightweight conceptual structures called folksonomies. Unlike ontologies, shared conceptualizations are not formalized, but rather implicit. We present a new data mining task, the mining of all frequent tri-concepts, together with an efficient algorithm, for discovering these implicit shared conceptualizations. Our approach extends the data mining task of discovering all closed itemsets to three-dimensional data structures to allow for mining folksonomies. We provide a formal definition of the problem, and present an efficient algorithm for its solution. Finally, we show the applicability of our approach on three large real-world examples.analysis, concept, fca, formal, myown, ontologyhandbook, trias